1. Field of the Invention
The invention relates to fiber-optic connector inspection microscopes and more particularly to an inspection microscope with an adaptive device, which allows the imaging axis of the microscope to be shifted in two mutually perpendicular directions, for inspecting individual endfaces of a fiber-optic connector having the endfaces arranged in multiple rows and multiple columns.
2. Description of the Related Art
The widespread implementation of fiber-optic communications for high-density interconnections has driven more and more multi-fiber connectors to be adopted in the industry. This creates an urgent need for regularly inspecting and maintaining the multi-fiber connectors in place, which are often situated behind backplanes or in locations which are very difficult to access.
It is well known in the fiber-optic communication industry that the endfaces of optical fibers within communication systems must be kept clean and undamaged, otherwise serious signal loss could result. The demand for cleanliness for fiber-optic endfaces has become even more stringent as the communication bandwidths increase and new communication technologies requiring higher laser power are applied.
Many types of microscopes are already available for inspecting endfaces of a fiber-optic connector to make sure the endfaces are undamaged and clean. Due to the need for sufficient magnification, the endfaces are typically inspected only one or two at a time. For a multi-fiber connector having optical fibers arranged in a single row, with the centers of the endfaces spaced typically at 0.25 mm, the microscope must be able to scan from one side to the other side of the connector in order to inspect each of the fiber-optic endfaces. Lately, multi-fiber connectors with optical fibers arranged in multiple rows (up to 6 rows and 12 optical fibers per row) have been developed and gradually adopted in the fiber-optics industry. For such multi-row fiber-optic connectors, the microscope must be able to shift its imaging axis, not only from side to side within each row but also from row to row, in order for all the endfaces to be inspected.
Cassady (U.S. Pat. Nos. 6,751,017 and 6,879,439) discloses a microscope for inspecting fiber-optic endfaces in a (single row) multi-fiber connector. The microscope comprises a slider assembly, a slider chassis and a drive assembly, in which the driver assembly interfaced with the slider assembly is capable of selectively displacing the slider chassis along an axis of motion to selectively direct the imaging axis of the microscope between adjacent fiber-optic endfaces.
U.S. Pat. No. 7,336,884 (to Zhou et al.) provides an adaptive device for inspecting fiber-optic endfaces arranged in a single row through the microscope. The device comprises a supporting body; a pendular arm rotatably mounted to the supporting body; a fitting tip attached to the pendular arm; and a bevel wheel fastened to the supporting body. The bevel wheel is adapted to swing the pendular arm relative to the supporting body so that the imaging axis of the microscope is shifted relative to the fitting tip to selectively align with the endfaces for inspection. However, with this device, the imaging axis of the microscope moves along a circular track relative to the fitting tip and may not be aligned with the center of some of the endfaces in a (single-row) multi-fiber connector.
U.S. Pat. No. 8,104,976 to Zhou et al. discloses an improved adaptive device for shifting the imaging axis of the microscope in a straight line over the endfaces of a single-row multi-fiber connector for inspecting the endfaces. The adaptive device is capable of bringing each endface of the multi-fiber connector into the field of view of the microscope for inspection. More specifically, the adaptive device comprises an adjustment driver and a swinging lever connected to a fitting tip, wherein the adjustment driver is adapted to swing the optical tube of the microscope relative to the swinging lever, thereby selectively shifting the imaging axis of the microscope relative to the fitting tip along a straight-line over the endfaces of a single-row multi-fiber connector interfaced with the fitting tip.
However, none of the inspection microscopes mentioned above are capable of shifting the microscope's imaging axis from one row of endfaces to another for selectively inspecting the endfaces of a multi-fiber connector having multiple rows of endfaces.
Therefore, an improved adaptive device for inspecting endfaces of a multi-row fiber-optic connector is needed, wherein the imaging axis of the microscope can be shifted relative to the fitting tip in two mutually perpendicular directions, so that the imaging axis can be precisely aligned with the center of each and every endface in the multi-row fiber-optic connector.